<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>IFE task 22</title>
    <link rel="stylesheet" href="css/style.css">
</head>
<body>

<div id="btn">
    <button id="preOrder">正序</button>
    <button id="inOrder">中序</button>
    <button id="postOrder">后序</button>
</div>
<div id="btn_speed">
    <button id="200">快</button>
    <button class="checked" id="500">中</button>
    <button id="800">慢</button>
</div>


<div id="root">
    <div class="left" id="1">
        <div class="left" id="2">
            <div class="right" id="3"></div>
        </div>
        <div class="right" id="4">
            <div class="left" id="5"></div>
            <div class="right" id="6"></div>
        </div>
    </div>
    <div class="right" id="7">
        <div class="left" id="8"></div>
        <div class="right" id="9">
            <div class="left" id="10"></div>
        </div>
    </div>
</div>

<script src="js/app.js"></script>
</body>
</html>